scale_y_seats <- function(name = 'Seats', seats = 435, label_every = 50, ...) {
  noms <- names(list(...))
  #name <- ifelse('name' %in% noms, list(...)['name'], 'Seats')
  breaks <- seq(0, seats, by = label_every) / seats
  if (max(breaks) != 1) breaks <- c(breaks, 1)
  if ('breaks' %in% noms) breaks <- list(...)['breaks']
  labels <- seq(0, seats, by = label_every)
  if (max(labels) != 1) labels <- c(labels, seats)
  scale_y_continuous(
    name = name, breaks = breaks,
    labels = labels,
    #trans = scales::trans_new('seats', function(x) x * seats, inverse = function(x) x / seats, domain = c(0, seats)),
    ...
  )
}
